PL1600 POST pass problem

Hi everybody,

I hope somebody has more experience than me, beause I lost all my ideas to solved this situation:

Few days ago, my Proliant 1600 "sandbox" server droped my ssh session, and has got no reaction for console commands. I have to reboot it. After this, I don't see the POST screen.No POST message, no beeps, nothing. The fans spinning, the array controllers flashing normal, HDD tray's LED flashed for a second, the IMD panel show only the fimware/model number...but I have got no boot screen on the monitor.